1. Field of the Invention
The present invention relates to "1 g" accelerometers as angle sensors for use in automotive, aircraft, ship, robotics and other applications. More particularly, the invention relates to a capacitive angle sensor that changes capacitance as a function of angular rotation by employing a vertical cantilever beam capacitor.
2. Description of the Related Art
Angle sensors can be used in a wide variety of applications. For example, angle sensors can be employed in automotive active suspensions to determine the angle of the control arm relative to the chassis, allowing calculation of the spacing of the wheel and chassis in real time. Angle sensors can be used as part of the attitude control mechanism in an aircraft or remotely piloted vehicle (RPV's), or as pitch and roll angle sensing devices on a ship. Angle sensing devices are also important in many robotics applications.
In these various angle sensing applications, it is necessary to accurately and continuously monitor the angle of the particular device in relation to some other device or reference point. Existing angle sensors employ a variety of techniques including: (1) a pendulum attached to the shaft of a potentiometer; (2) a curved tube containing an electrolyte that shunts resistance elements, connected as adjacent legs of a Wheatstone Bridge, as the tube is tilted; and (3) differential cooling of resistance elements by an enclosed gas, due to convection, that is a function of the tilt angle. All of these angle sensors are relatively large, mechanically complicated, and subject to various degrees of sensitivity and accuracy.
Therefore, a need exists for an accurate, sensitive, low cost and relatively simple angle sensor that can be adapted to perform in a wide variety of applications.